Mercury spark gap



w. F. G. swANN MERCURY SPARK GAP Filed Deo.

Patented Dec.' 1, 1931 UNITED'STATES WILLIAM F. G. swANmoF swnn'rrmon, rENNsYLvANrA; fi L MERCURY SPARK GAP Application mea December 5, seriaiiro'.- 411,9ea

The present invention relates to mercury evacuated vessel of improved form which is ,Y more rugged and durable than those made VAD Clt

in accordance with constructions ofthe prior art.

further object is to provide a construe# tion of a spark gap which willwithstand the severe strain of continuous operation and of atmospheric pressure.

Other objects and advantagesof the invention will appear more fully hereinafter from the following detailed description together with the drawings, in which:

Fig. 1 isa vertical sectional view of the device; and Y Fig.` 2 is a plan sectional view taken on the line22 of Fig. 1.- y

The device comprises a hollow spherical vessel lma'de of refractory glassor of any other suitable refractory material,l having integral therewith a short hollowcylindrical portion 10.A Extending from the cylindrical Vportionupwardly into the spherical chamber 2 is amember 3 which is made integral with the walls of the vessel. The member comprises a tubular neck portionl having a vconc cavo-convex head, the convex sides of which may be substantially parallel to the walls ofA the chamber 2. The concave portion is provided for the reception of a quantity of mercury indicated at 5 which is permitted to flow down into the tubular portion by means of the canal 12 so that the mercury may come in contact with a terminal 7.V 'The convex sides of the member 3V also form a mercuryreceiving space with the walls ofthe chamber,

2 and it extends down into the cylindrical portion 10, as indicated at 11, so as to permit the mercury indicated at 4 to come into contactwith another terminal 6'. It will be seen that the mercury-receiving space of the chamber 2 is insulatingly separated from the con Y cave mercury-receiving space by means of the rounded: portion13 of l'the member 3, thus forming an electrical gap-between'the mer# cury at 4 and fwhi'ch maybe traversed vby a spark'when an electric current is introduced" at' the terminals 6 and' 7. *The chamber 2 is evacuated at the point 8 and sealed. The body l-is made sphericaliso asl to enable it to resist strains arising fromatmospheric pressureff` p' l y In the preferred embodiment of my inventi011', the member 3 is also hollow andbmay be L evacuated at the point9,"although it may be inade Vofsolid refractory glass integral with lthe body portion 1 if desired,"without de-j` parting fromthe scope of the invention., The y 05"' provision of themember 3, which is the novel y feature'of the invention, is to provide a means by which the, two portions 'of mercury may be insulated from each other without de arting'tromk an external lspherical shape o ,the apparatus.. fMoreover, the construction lis such that 'the weight ofthe mercury will not easily break the glass, andsuch thaty the neck portion o'f'thevessel will be insulated from the highheat which is present at the portion 13 when the spark gap is in operation, which heat also tends tobreak the glass.` The evacuation of the member 3 contributes l'to the strength of 'the yentire vessel since there .is no. appreciable dilierence yof pressure between the chamber 2 'and the inside of the member 3. j

.Thev spark.k gaps 'of the prior art generally comprise a conical evacuated glass vessel'with a mercury-receiving space-1n the base porsi y tion of the vessel, and the necessity of sepa` rating the two portions of the mercury results 65T ini an external form which is weak asregards support of the mercury and they strain of external atmospheric pressure. 'Such de Y vices can seldom'be used, for more than three minutes 'of continuous operation, while the vof the cylin l extending into said chamber to provide an device of my invention has been successfully operated continuously for more than four hours Without showing any signs of the glass vessel cracking or tending to break. The ability of the device to withstand the great strain of continuous operation renders it serviceable Where it is desired to maintain a mercury spark for long periods of time, which had been heretofore impossible.

Vhile I have shown only one embodiment of my invention, for purposes of illustration and description, it is obvious that other changes andmodilications may be made Without departing from the scope thereof and I, therefore, desire to be limited only by the scope of the appended claims.

l claim:

its convex surface disposed in substantially parallel relation therewith to provide a mercury-receiving space, and a terminal extending from the space through the wall of said first member, said second member having means communicating with the concave portion downwardly to another terminal so that an annular spark gap is formed when said concavity and said space are illed with mercury.

WILLIAM F. G. SVVANN.

l. A device of the class described cone-w` prising a spherical chamber, and a second chamber supported Within and from the walls are filled with mercury.

21A mercury spark gap comprising an evacuated spherical chamber, and an evacuated member supported within and from the Walls of the chamber combining with said Walls to provide a mercury-receiving space, said member having a concave portion to pro vide another mercury-receiving space so as to form a gap when said spaces are illed with mercury.

3. A mercury spark gap comprising an evacuated'spherical chamber, and an evacuated member supported within and from the Walls of the chamber combining with said Walls to provide an outer annular mercuryreceiving space underlying the external surace of the member, said member having a concave portion to provide'an inner mercuryreceiving space so as to form an annular gap when said spaces are filled with mercury.`

4. A device of the class described comprising an evacuated spherical chamber having a cylindrical portion, and a hollow evacuated member supcported within and from the Walls rical portion of the chamber and outer annular mercury-receiving space underlying the external surface of the member, said member having a concave portion at its upper end to provide an inner mercury-receiving space so as to form an annular gap When said spaces are filled with mercury.

5. A device of the class described comprising a hollow evacuated member having a spherical head and a cylindrical neck, another hollow evacuated member having a concavo-convex head and a cylindrical neck disposed'within said first member with its concavity extending upwardly into the spherical chamber of said first member and 

